arch/arm64/include/asm/syscall.h

   1 /*
   2  * Copyright (C) 2012 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #ifndef __ASM_SYSCALL_H
  17 #define __ASM_SYSCALL_H
  18
  19 #include <uapi/linux/audit.h>
  20 #include <linux/compat.h>
  21 #include <linux/err.h>
  22
  23 extern const void *sys_call_table[];
  24
  25 static inline int syscall_get_nr(struct task_struct *task,
  26                                  struct pt_regs *regs)
  27 {
  28         return regs->syscallno;
  29 }
  30
  31 static inline void syscall_rollback(struct task_struct *task,
  32                                     struct pt_regs *regs)
  33 {
  34         regs->regs[0] = regs->orig_x0;
  35 }
  36
  37
  38 static inline long syscall_get_error(struct task_struct *task,
  39                                      struct pt_regs *regs)
  40 {
  41         unsigned long error = regs->regs[0];
  42         return IS_ERR_VALUE(error) ? error : 0;
  43 }
  44
  45 static inline long syscall_get_return_value(struct task_struct *task,
  46                                             struct pt_regs *regs)
  47 {
  48         return regs->regs[0];
  49 }
  50
  51 static inline void syscall_set_return_value(struct task_struct *task,
  52                                             struct pt_regs *regs,
  53                                             int error, long val)
  54 {
  55         regs->regs[0] = (long) error ? error : val;
  56 }
  57
  58 #define SYSCALL_MAX_ARGS 6
  59
  60 static inline void syscall_get_arguments(struct task_struct *task,
  61                                          struct pt_regs *regs,
  62                                          unsigned int i, unsigned int n,
  63                                          unsigned long *args)
  64 {
  65         if (n == 0)
  66                 return;
  67
  68         if (i + n > SYSCALL_MAX_ARGS) {
  69                 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  70                 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  71                 pr_warning("%s called with max args %d, handling only %d\n",
  72                            __func__, i + n, SYSCALL_MAX_ARGS);
  73                 memset(args_bad, 0, n_bad * sizeof(args[0]));
  74         }
  75
  76         if (i == 0) {
  77                 args[0] = regs->orig_x0;
  78                 args++;
  79                 i++;
  80                 n--;
  81         }
  82
  83         memcpy(args, &regs->regs[i], n * sizeof(args[0]));
  84 }
  85
  86 static inline void syscall_set_arguments(struct task_struct *task,
  87                                          struct pt_regs *regs,
  88                                          unsigned int i, unsigned int n,
  89                                          const unsigned long *args)
  90 {
  91         if (n == 0)
  92                 return;
  93
  94         if (i + n > SYSCALL_MAX_ARGS) {
  95                 pr_warning("%s called with max args %d, handling only %d\n",
  96                            __func__, i + n, SYSCALL_MAX_ARGS);
  97                 n = SYSCALL_MAX_ARGS - i;
  98         }
  99
 100         if (i == 0) {
 101                 regs->orig_x0 = args[0];
 102                 args++;
 103                 i++;
 104                 n--;
 105         }
 106
 107         memcpy(&regs->regs[i], args, n * sizeof(args[0]));
 108 }
 109
 110 /*
 111  * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
 112  * AArch64 has the same system calls both on little- and big- endian.
 113  */
 114 static inline int syscall_get_arch(void)
 115 {
 116         if (is_compat_task())
 117                 return AUDIT_ARCH_ARM;
 118
 119         return AUDIT_ARCH_AARCH64;
 120 }
 121
 122 #endif  /* __ASM_SYSCALL_H */